Currently, in a Long Term Evolution (LTE) system, user equipment (UE) detects downlink control information (DCI) in a downlink subframe. The DCI includes scheduling information used by the UE to send a physical uplink shared channel (PUSCH) and scheduling information used by the UE to receive a physical downlink shared channel (PDSCH), for example, a quantity of physical resource blocks used in a frequency domain, a used modulation and coding scheme or modulation scheme, and a quantity of bits included in a carried transport block. The PUSCH channel mainly carries uplink data sent by a terminal, and is sent by means of single-carrier frequency division multiple access (SC-FDMA). A smallest scheduling granularity in the frequency domain is one physical resource block (PRB). One PRB includes 12 orthogonal subcarriers in the frequency domain, and a subcarrier spacing is 15 kHz. Therefore, one PRB includes a 180 kHz frequency resource.
However, with rapid development of communications technologies, an LTE terminal that can support a plurality of types of terminal capabilities has been available. For example, that a terminal supports a type 1 terminal capability means that a terminal can send a single subcarrier by means of SC-FDMA at an orthogonal subcarrier spacing of 3.75 kHz in uplink, or send a single sub-channel by means of FDMA at a sub-channel bandbandwith of 3.75 kHz in uplink; that a terminal supports a type 2 terminal capability means that a terminal can send a single subcarrier by means of SC-FDMA at an orthogonal subcarrier spacing of 15 kHz in uplink; or that a terminal supports a type 3 terminal capability means that a terminal can send a plurality of subcarriers by means of SC-FDMA at an orthogonal subcarrier spacing of 15 kHz in uplink. A terminal that supports all of the three types of terminal capabilities supports an orthogonal frequency division multiple access (OFDMA) technology in downlink, and a subcarrier spacing is 15 kHz. The terminal can support any one or more of the three types of terminal capabilities.
However, the smallest scheduling granularity of the LTE system is one PRB, that is, a 180 kHz frequency resource, scheduling of a single subcarrier or a plurality of subcarriers is not supported, and a radio frequency bandwith of the terminal that supports the type 1 terminal capability and the type 2 terminal capability ranges from 3.75 kHz to 180 kHz. Therefore, the LTE system cannot receive information on a synchronization channel or a broadcast channel in the existing LTE system, and cannot perform communication normally. In this case, a data transmission method and an apparatus are urgently required.